This invention relates to the forming of a metal product by extrusion.
In British Patent Specification No. 1370894, there is described a method of, and apparatus for, continuously extruding metal. The apparatus comprises a rotatable wheel having an endless groove extending around its periphery, a fixed structure covering the groove along part of its length to define a passageway therewith, a blocking member projecting into the groove to close off one end of the passageway and a die orifice leading from the closed off passageway adjacent said blocking member. In use, the wheel is rotated relative to the fixed structure and metal rod to be extruded is fed into the end of the passageway away from the blocking member and the metal is carried along in the groove by frictional drag in the direction towards the blocking member and is forced through the die orifice to produce the metal product.
In this British specification, it is clear that it is intended that metal which is fed into the passageway is in the form of a solid rod, although there is a suggestion in the specification that the metal may be of powder form when it is introduced into the passageway. Clearly, when the metal to be extruded is in the form of a rod, then the rod has been made from molten metal elsewhere and has probably been rolled to the required cross-section and then transported to the extrusion apparatus.